1. Field
Exemplary Embodiments relate to a method and apparatus for coding and decoding an audio signal, e.g., a speech signal or a music signal, and more particularly, to a method and apparatus for coding and decoding a signal corresponding to a high-frequency band of an audio signal.
2. Description of the Related Art
A signal corresponding to a high-frequency band is less sensitive to a fine structure of frequency than a signal corresponding to a low-frequency band. Thus, when coding efficiency is increased to eliminate restrictions in relation to bits available to code an audio signal, a large number of bits are assigned to the signal corresponding to the low-frequency band and a relatively small number of bits are assigned to the signal corresponding to the high-frequency band.
A technology employing the above method is spectral band replication (SBR). In SBR, coding efficiency is increased by expressing a high-frequency signal with an envelope and synthesizing the envelope during a decoding process. SBR is based on hearing characteristics of humans and has a relatively low resolution with regard to a high-frequency signal.